1. Field of the Invention
The present invention relates to a rotary shear adapted to be actuated upon order change for cutting a running corrugated cardboard web or forming a slitting slot in the direction of its lateral width.
2. Description of the Prior Art
A description will be made of the construction and function (operation) of a rotary shear in the prior art with reference to FIGS. 6 to 10. A rotary shear is an apparatus acting upon a corrugated cardboard web 6 manufactured continuously in a corrugating machine. A process for cutting or applying a slitting slot working across its widthwise direction will be described. This apparatus operates at the time of order change, and has a function of dealing with resetting such as change of a set width of a trim 8, a set width of a sheet 7, and the like. In the following, a construction and a function of a rotary shear in the prior art will be explained with reference to FIG. 7.
As shown in FIG. 7, a knife cylinder 2 having a knife 1 fixedly secured thereto has its opposite sides pivotably supported via bearings 16a and 16b from frames 5a and 5b erected at the opposite widthwise ends of the apparatus, a gear 17 is fixedly secured to its axial end portion on one side, and further to its outermost axial end is connected a shaft 19 via an electromagnetic clutch brake 18. To the same shaft 19 is mounted a pulley 20, and the same shaft 19 and a line shaft 21 are connected by means of a pulley 22 fixedly secured to the line shaft 21 and a belt 23. On the other hand, an anvil cylinder 24 is pivotably supported at its opposite ends via bearings 25a and 26b from the frames 5a and 5b as juxtaposed with the above-described knife cylinder 2. A shaft at one side end of the anvil cylinder 24 is connected to a shaft 27 via an electromagnetic clutch brake 26. To the shaft 27 is fixedly secured a gear 28, which is meshed with the gear 17 fixedly secured to the above-described knife cylinder 2. Also, to a shaft at the other side end of the anvil cylinder 24 is fixedly secured a pulley 29, and the same pulley 29 is connected to a pulley 32 fixedly secured to a shaft 31 via a belt 30. Furthermore, the shaft 31 is connected to an indexing motor 34 via an electromagnetic clutch brake 33. It is to be noted that in FIG. 7, reference numeral 6 designates a corrugated cardboard web traveling through a gap clearance between the anvil cylinder 24 and the knife cylinder 2 as held in rolling contact with the anvil cylinder 24.
As shown in a developed form in FIG. 9, the surface of the above-mentioned anvil cylinder 24 has steps (protrusions and recesses) formed in a part of the circumferential surface by removing the central portion of the anvil (elastic body) 35 over a successively decreasing length from the portion extending over the entire width L up to the portion having a predetermined length L.sub.o. Accordingly, by differently setting a relative phase of the anvil cylinder 24 to be engaged with the knife 1 on the knife cylinder 2, various cutting works as shown in FIG. 10 can be achieved. That is, if the anvil cylinder 24 is engaged with the knife 1 at the position A in FIG. 9, then perfect cutting over the entire width can be done, while if it is engaged with the knife 1 at the position B in FIG. 9, then slitting slots corresponding to the length P.sub.o in FIGS. 9 and 10 can be formed at the opposite end portions of the width of the corrugated cardboard web 6. At the time of formation of the above-mentioned slitting slots, the portion corresponding to the length P in FIGS. 9 and 10 is a recessed portion formed on the roll surface of the anvil cylinder 24, accordingly, in this portion a pinching force (cutting force) between the roll surface and the knife 1 is not generated, and hence cutting is not effected. As described above, in the rotary shear of the illustrated type, provision is made such that by appropriately and variably setting the position B where the roll surface is engaged with the knife 1, slots having an arbitrary length of zero to a maximum (W-L.sub.o)/2 can be machined at the opposite widthwise end portions of the corrugated cardboard web 6 (where W indicates a width of the corrugated cardboard web). FIG. 8 is a perspective view showing an operating state of the rotary shear, which clarifies an engaging state of the circumferential surface of the anvil cylinder 24 and the knife 1 on the knife cylinder 2 to be engaged, and a machining state for the traveling corrugated cardboard web 6.
Now, description will be made on a function of the above-described rotary shear.
As initial setting of the rotary shear, at first the electromagnetic clutch brake 26 is released, and after the interlocking with the knife cylinder 2 has been released, the electromagnetic clutch brake 33 in the section of the indexing motor 34 is actuated to connect, and by driving the same motor 34, a relative phase with respect to the knife 1 corresponding to a desired cut and machined state of the corrugated cardboard web 6 is adjustably realized (indexed). Subsequently, the electromagnetic clutch brake 33 is released, also the above-described electromagnetic clutch brake 26 is connected, and thereby setting is made so as to maintain the relative phase between the respective cylinders 2 and 24 and to interlock them with each other. In succession, the electromagnetic clutch brake 18 is actuated, and by switching on and off the power transmitted from the line shaft 21 at a predetermined timing, a slitting work or a cutting work is applied to the traveling corrugated cardboard web 6.
FIG. 12 is a schematic view of a slitter-scorer section positioned in the next step of process, and FIG. 11 illustrates a worked state of a corrugated cardboard sheet so as to correspond vertically in position to FIG. 12. Slitter-scorers Pa and Pb are apparatuses for applying predetermined score lines K and slitting slots S to a traveling corrugated cardboard web 6 by means of equipped scoring rolls 36a and 36b and slitter knives 37a and 37b as shown in FIGS. 11 and 12, and it is adapted to simultaneously manufacture a plurality of sheets (multiple manufacture) by properly selecting a corrugated cardboard web width W in relation to a product sheet width W.sub.o (FIG. 11 shows the case of double manufacture.). Also, in order to realize shortening of the time for resetting caused by order change, often the slitter-scorers are installed two sets Pa and Pb as aligned in the direction of traveling of sheets. It is to be noted that the entire width W of the above-described cardboard web under manufacture is chosen somewhat broader than the width W.sub.o to be used as product sheets, hence the opposite widthwise end portions where displacement or squeeze-out of paste at the time of sticking raw paper webs is liable to occur, are cut in a strip form, and they are sucked into the respective trim ducts 38 as waste paper sheets to be dealt with. The rotary shear in the prior art was an apparatus to be operated mainly as a trim shear that is useful for cutting the leading ends of the necessitated new order side trims 8a at the time of switching between slitter-scorers Pa and Pb as a result of an order change, that is, at the time of changing disposal of the trims 8 formed in correspondence to the width W of the corrugated cardboard web under manufacture and the width W.sub.o of the product sheets.
Next, brief explanation will be made on change of setting of the rotary shear in the prior art, which is operated as a trim shear.
With regard to change of a trimming position, in response to a signal issued from an order change system control unit not shown, besides setting in position of a trim duct 38b, various settings corresponding to the new order are effected in the slitter-scorer Pb in a standby state, and at the same time in a trim cutting device (rotary shear), for the purpose of setting a cut-away amount at the opposite widthwise ends of the corrugated cardboard web corresponding to the new order, a relative angular position of the anvil cylinder 24 with respect to the position of the knife 1 is preset. Subsequently, the knife cylinder 2 and the anvil cylinder 24 are rotated as opposed to each other at a predetermined timing for the corrugated cardboard web 6 to travel and pass therebetween, and a trim cutting notch is applied to a desired position. Next, the same notch position is transferred to the slitter-scorer Pb under a standby state, at first the scoring roll 36b is engaged at a predetermined position, subsequently the slitter knife 37b is engaged, and successively working according to the new order is effected. On the other hand, in a slitter-scorer Pa which has been working according to the old order, at a predetermined timing when the leading end of the corrugated cardboard sheet according to the new order reaches, the engagements with the scoring roll 36a and the slitter knife 37a are successively released. The new trims 8b produced from the corrugated cardboard web 6 according to the new order are respectively sucked and conveyed into a pair of newly set trim ducts 38b in a slitter-scorer Pb for use according to the new order, and after they have been shredded by a cutter-blower 39 equipped in the midway, they would be dealt with.
The rotary shear in the prior art was constructed and operated in the above-described manner, and it had only two kinds of functions of forming slitting slots of arbitrary length at the opposite widthwise ends of a traveling corrugated cardboard web, or perfectly cutting the same web over its entire width. Accordingly, as shown in FIG. 11, in setting of double manufacture, the specification can be stably switched only under a limited condition such that only the width of trims 8a at the ends of the width is changed according to order change, that is, the slitting slots for isolating sheets are continuous, in the case where cut lengths of two sheets traveling in parallel are the same even if the same slitting slots for isolating sheets should become discontinuous as a result of change of the sheet widths, or in the case where only one kind of sheets are manufactured from one web not shown. However, upon change of the specification according to order change, in many cases not only the widthwise dimension of the sheet 7 changes but also cut lengths of the two sheets 7 traveling in parallel are also arbitrarily changed as shown in FIG. 6. In double manufacture, wherein two kinds of sheets are manufactured in parallel from a single corrugated cardboard web, in the case where the cut lengths of the sheets traveling in parallel are different from each other, a traveling route of the sheet on one side is changed at a cut-off in the downstream step of process not shown, and they are cut into predetermined lengths by transferring them respectively to separate rotary drum shears.
Accordingly, in the case where the specification has been changed, for instance, as illustrated in FIG. 6, a discontinuous portion marked * would remain in the central slitting slot, and so, at the time of change of the traveling route (separation to the above and the below) at the cut off in the downstream step of process carried out in the event that the lengths of the above-described sheets traveling in parallel are different from each other, not only the above-described discontinuous portion would break and become unacceptable paper sheets, but also troubles such that the broken pieces of sheet are engaged with conveying means at the downstream (feed rolls) resulting in jam-up, would occur frequently. From these reasons, in the rotary shear in the prior art, in the case where the position of the slitting slot for isolating the sheet is to be changed, the method of once cutting and separating the preceding and succeeding corrugated cardboard web portions over their entire width at the time of order change and thereby obviating damage of the sheets occurring at the above-described discontinuous portion (the portion marked * in FIG. 6), was employed. However, this method has a shortcoming that restraint of a trailing end of an old order sheet and a leading end of a new order sheet would temporarily become free, and hence zig-zag traveling of sheets 7 and variation of a conveying velocity would occur. Consequently, precision in the cut length and the like would become not guaranteed, and would become a principal cause of various troubles which may possibly occur during the period before a new sheet traveling condition becomes stable.
As described in the preceding paragraphs, the rotary shears in the prior art could achieve only two kinds of cutting works of machining slitting slots in the widthwise direction of a sheet at the opposite ends of a width of a corrugated cardboard web, and perfectly cutting a sheet over its entire width. Accordingly, although a sheet can be dealt with (switched) smoothly by slitting slots formed at the opposite ends of a width under a limited condition such that only a trim width is changed as a result of order change, in multiple manufacture wherein two kinds (a multiple of kinds) of sheets having different lengths are manufactured from a single corrugated cardboard web, for instance, in the case where a width of sheets is changed at the order change and cut sheet lengths are different, then a slitting position is displaced in the widthwise direction of a sheet at a change point between the old and new orders, resulting in a discontinuous portion, hence the sheet would break as a result of separation of a sheet traveling route at a cut-off in the next step of process, and the sheet would become an unacceptable paper sheet. Not only such troubles, but also it would become a principal cause of various troubles such that the broken sheet pieces may plug the space between conveyor rolls in the next step of process and may cause jam-up. While, in the case where the sheet has been cut perfectly in the widthwise direction at the portion of the order change as a counter-measure for the above-described problems, though the disadvantage of breaking at the slitting position is eliminated, another problem would arise such that the ends of the new and old sheets would become free, hence the conveying condition becomes unstable, therefore the sheets would travel in a zig-zag manner or the traveling speed (amount) would vary, and a precision in a cutting dimension at the cut-off in the next step of process would be deteriorated.